1. The Field of the Invention
This invention relates to cordless telephone devices. More particularly, the present invention relates to apparatus and methods for adding cordless handset capability to an existing corded telephone.
2. The Prior Art
The telephone has become an indispensable part of a modern society. Voice communications between people separated by thousands of miles has become commonplace. Telephone service has become so pervasive that mobile telephone service is available in automobiles and commercial aircraft and portable telephones may be carried and used by a person nearly any place a person might want to venture.
The availability of mobile (installed in a vehicle or craft of some type) and portable (battery operated and self contained) telephones has caused consumers to expect instant telephone communications service wherever they roam. In many areas, large numbers of residences now have one or more cordless telephones. Consumers have now come to expect that the freedom which a mobile, portable, or cordless telephone provides will be available everywhere.
When a mobile, portable, or cordless telephone is not available, corded telephones still continue to be widely used. A corded telephone includes a base housing the necessary electrical circuitry and providing a keypad or rotary dial set. The corded base unit has a line jack which is interconnected by wires or cable to a telephone network. The corded base unit also provides a handset jack which is connected by wires or a cable to a handset having a handset receiver and a handset transmitter.
In contrast to a corded telephone, a cordless telephone is one which comprises a handset which includes a wireless transmitter and a wireless receiver which communicate with a cordless base which includes a corresponding wireless transmitter and receiver. The base unit has a line jack which is connected by wires or cables to a telephone network as in the case of a corded telephone.
With a cordless telephone, a user can roam distances from the base unit without the restrictions imposed by the handset cord. In comparison, the user of a corded telephone is limited in the distance from the base unit that can be traveled by the length of the cord between the handset and the base unit. Moreover, the handset cord often becomes inconveniently tangled.
While cordless telephones have become commonplace in residential use, cordless telephones are not widely used in business applications. This is so even though users of business telephone systems have long desired cordless telephones in their business settings.
One reason for the lack of cordless telephone capability in business settings is that the capital investment in existing corded business telephone equipment is very substantial. Due to the large capital investment in corded telephone equipment, prudent business people are hesitant to discard existing corded telephone equipment merely to add cordless handset capability to an existing business telephone system. Moreover, in most business settings, a business telephone must interconnect with a business' telephone system rather than with the local telephone network. Thus, a business user must find a cordless business telephone which is compatible with the existing business telephone system or face the choice of replacing or modifying the business telephone system to add cordless handset capability.
In view of the above described problems in the prior art, it would be an advance in the art to provide a system and method for economically adding cordless handset capability to an existing corded telephone without making any permanent modifications to the existing corded telephone. It would also be an advance in the art to provide a system and method for adding cordless handset capability to an existing corded telephone which takes a minimum of time to install on the existing corded telephone and does not require any internal modification to the telephone or to the telephone system to which it is connected.